P4Killer_'s first go at a 4th Order

[P4killer_]

what are the specs on your box ?? ratio and such?

Roughly with the 2x2's and woofer displacement accounted for its 2.6 cubes sealed, 1.6 ported with 2 4" ports @ ~57.6 Hz. Maybe down the line, Ill put more power too the subs, Id really like to see what happens then. For this little amp, at least to my ears, its kinda impressive

[uhoh_45]

Roughly with the 2x2's and woofer displacement accounted for its 2.6 cubes sealed, 1.6 ported with 2 4" ports @ ~57.6 Hz. Maybe down the line, Ill put more power too the subs, Id really like to see what happens then. For this little amp, at least to my ears, its kinda impressive

you got that all wrong... i just did a sketchup of what i'd do and came out with .9 sealed per sub with a 3-1 ratio bringing it to 2.7 cubes ported

so 1.8 cubes sealed and 5.4 cubes ported tuned to 48

so 7.2 cube box... big box

hell even covering up those ports and turning your ported area into sealed area might benefit you

[P4killer_]

Covering my ports means dual sealed mean zero output. Im not a 4th order wizard by any means, but ill give you a pic of what I used

[P4killer_]

So unless this entire calculator is backwards, its designed to spec

[uhoh_45]

i dont go off calculators like this i go off 2-1 3-1 4-1 ratio

(ported to sealed ratio) i like 3-1 myself but is often big 2-1 is good for daily where as 4-1 is real peaky ha

the bigger the ported area the more efficient the subs will be

as for what i said bout cover ports i meant

turn your ported area into the sealed area and the sealed area into the ported area

cover up the port holes and re-drill them on the old sealed side

[P4killer_]

Im sure your're very knowledgable and all, but you are essentially saying what Ive learned is backward. Even in WiniSd it comes up with essentially the very same spec as far as the box goes. So maybe in awhile Ill do as you have suggessted, but until then, Id like to know why you have come to these conclusions. Or could you maybe offer your sources ie:. something to read in regards to theory. And although, in your opinion Ive built it backward, the output is decent given what it is and according to you, it would be better ie:. ill gain by simply reporting on the other side.. why? Ive no problem being corrected, but it will do me no help if I cant understand why.

Thanks alot for your help, and hopefully you can enlighten me

[dwright27]

As soon I read the specs I was like that's ass backwards.

I was like his numbers should e higher but I see why they aren't now. As stated id do around 1 - 1.5 sealed, and 2 - 3 ported with around 40 - 50 square inches of port tuned around 45 hz

[P4killer_]

But again the question is, WHY? If winisd and a few calcs online basically render the same reccomended specs, then why are they wrong>? knowledge was really the only goal is this project, and Id LOVE to learn as much as possible about this before working on a bigger scale. Its like letting someone else build for you, just because they did it for you and it pounds, means you yourself have learned nothing, and whats the point of that?

[uhoh_45]

i've talked to 80inches about bandpass's and learned alot from him

quote from 80 himself

well u usually do a 1:2 ratio for daily and if i can get a 1:4 ratio daily i will do it..cuz the bigger the ported chamber the more efficient the entire box is.

i cant provide sources but the way i learnt was getting basics down

people told me generally for an 18" sub you need roughly 1.75-2 cubes sealed for a 15 you need roughly 1.3-1.6 cubes sealed and for a 12 roughly .8-1.3 sealed

so i took those averages and played with them with different ratios and learnt from there

its hard to explain everything but generally the ported area should be bigger then sealed

and it should tuned roughly to 47-50 hz

[hard_nox]

Put up a vid of the box, I am working on the same idea except I am going to port through the rear deck. Got measurements on that box?